Flooded boiler steam or spray iron



NOV- 10 1954 w. Ev DAVIDSON FLooDED BOILER STEAM 0R SPRAY IRON Filed 0G19. 9, 1962 n, ww wwwkqv .nm MM l/M 0 w f ef Mm Q Vm A MM .W ha a mmm W 1W ./.MmM

United States Patent O 3,156,054 FLOODED EEILEER STEAM R SPRAY IRN William E. Davidson, Unitario, Calif., assigner' to General Electric Company, a corporation of New Yori: Filed Get. 9, i962, Ser. No. 229,374 6 Claims. (Cl. '3S- 77) This invention relates to pressing irons of the type having provision for creating steam to be used for moistcning the fabric being pressed, and more particularly relates to an improved arrangement for generating and delivering low temperature wet steam even at high temperature settings and at a rate which varies with the temperature setting of the iron.

One known method of generating steam in an iron having a self-contained water supply is to heat the entire supply to lthe boiling temperature. Another common method is to allow water to drip from a supply reservoir into a liash steam generator wherein each drop is then immediately ashed into steam. The first arrangement, commonly referred to as the tea kettle7 type, usually provides very wet low temperature steam which is excellent for dampening fabric; however, a major drawback of such an arrangement is that since no steam is available until all of the water is brought to the boiling temperature, initial operation is objectionably slow.

T he flash steam generator design has the great advantage of providing very quick steam operation after starting with a cold iron; but to accomplish this rapid vaporization, it is necessary to have relatively high temperature for the metallic components in which steam is generated and delivered. Accordingly, the steam formed thereby is relatively dry and has a superheated temperature substantially above the water boiling temperature. Such steam is not as satisfactory as a lower temperature wet steam for moistening fabrics, in that suflicient liquid may not condense on the fabric to assist adequately in the pressing operation. Also the steam rate does not vary with the temperature setting.

While steam irons employing the flash steam generator principle have been particularly successful commercially, experience has shown that there are certain manufacturing and maintenance problems. Such an iron necessarily requires a very small orifice leading from the liquid reservoir to the flash steam generator, through which water flows, drop by drop. Occasionally, during manufacture, a lrn can tend to develop on the metallic parts in the vicinity of the orifice. Since this film is water repellent, the result is that water refuses to iiow through the small opening, such a malfunction being known in the art as a dry film condition. Furthermore', after extended periods of operation, the small orifice tends to become clogged with mineral deposits or flakes of scale or other foreign particles which find their way into the liquid reservoir and subsequently into the liquid orice.

A third known method of providing steam in irons is to maintain a small quantity of water at the boiling temperature while the reservoir supply is kept below boiling temperature. Such an arrangement provides the advantage of wet steam like the tea kettle type iron and the.

speed advantage of the dash steam generator, while not having the drawbacks of the other two types. Another benefit is that the steam generation rate may be varied with the temperature of iron soleplate or pressing surface.

It is a primary object of the present invention to provide a pressing iron having an improved arrangement for rapidly furnishing a supply of low temperature, wet steam.

Another object of the invention is to provide a flatiron of the type having a small flooded boiler with a unique heat insulating member for separating steam from ICC the water in the boiler and ducting the steam to the material to be pressed.

It is a further object of the invention to provide an improved flatiron having a relatively small steam generating chamber which is kept flooded whenever steam is being produced and which will automatically stop providing steam whenever the iron is placed upon its heel rest.

In accomplishment of the foregoing objectives and in accordance with one aspect of the present invention, there is provided a iiatiron having a soleplate, a boiler, a Water eservoir and a heating element for heating the soleplate and the boiler. A restricted liquid connection between the reservoir and the boiler permits water flow into the boiler at a rate greater than the rate at which steam is formed in the boiler, so that the boiler remains iiooded while heat transfer to the reservoir is minimized. Steam formed Within the boiler is separated from the remaining boiler water by liowing into the reservoir and is then ducted to the fabric to be ironed by way of a steam passage exciting through the iron soleplate or by way of a spray mechanism incorporated in the iron. The capacity of the steam boiler is relatively small, so that the boiler is kept flooded during the steaming operation, thus providing a quick supply of wet steam.

Further features, objects and attendant advantages will become apparent with reference to the drawing which is a side elevation, partially in section, of a steam and liquid spray iron incorporating the improved hooded boiler concept of the invention.

Referring to the drawing, there is shown a flatiron of the domestic type having a soleplate 1, to which is secured in any desired and Well known manner an outer shell 2 and handle 3. Soleplate l may be heated electrically by means of a sheath type heating element comprising an outer metallic sheath 4, in which is located centrally an electrical heating element 5 spaced and insulated from the outer sheath by a compound such as highly compressed and granulated magnesium oxide. This heating element is, of course, supplied with electrical power from a suitable supply cord 6.' The temperature of the soleplate of the iron may be adjustably controlled by any suitable thermostatic switch mechanism (not shown) of a well known type adjustable to select the desired temperature by a manually operable member 7 extending outwardly through the front handle support.

The soleplate l is provided with a steam generatingror boiler cavity S, located preferably within the closed end of the heating element loop embedded within the lsoleplate. Cavity 8 defines a relatively small volume, so that when the cavity is filled with water, conversion of water to steam will take place quickly. The boiler 8 is sepa- -rated by a ridge 9 from a steam passageway 1t? formed by the upper surface of the soleplate and a cover'assembly 12. The passageway leads to a plurality of steam outlet ports, one of which is shown at 11, which duct steam to the ironing surface of the soleplate. Boiler 3 and steam passageway 10 are separated and partially trol housing Ztl positioned over the boiler 8 extends up- Y wardly through the opening-in reservoir bottom Wall 16 into the upper portion of the reservoir 15.

As shown, housing 20 is supported on the upper surface of cover plate liner 1 4. The reservoir bottom wall 3 16 in turn, rests on an annular flange 21 formed integral with housing 20. Upon assembly, the reservoir is pressed downwardly to form a steam pressure tight seal at the housing flange 21 with the reservoir and cover plate liner 14.

In accordance with this invention, the steam control housing is a multi-purpose, molded member made of a suitable heat insulating material to minimize the transfer of heat from the boiler and the generated steam to the water in the reservoir. In practice, this housingy has been molded satisfactorily from a silicone rubber compound, which simultaneously provides the necessary structural features and withstands the operating temperatures expected in a flatiron. The lower wall 22 of the silicone rubber'housing forms the upper wall for the boiler 8 and contains an opening 23 which provides somewhat limited liquid communication from the reservoir to the boiler. In the drawing, opening 23 is shown blocked by valve steam 24 extending upwardly through `the reservoir and handle to a manual control button 25 shown in solid lines in its depressed position and in broken lines in its upper position. The button is formed with a shoulder 25a adapted to cooperate with an internal portion of the handle to latch the button in the depressed position when so placed.

The steam generating cavity 8 is relatively small and is removed appreciably from the heating element, although there is a direct metallic heat flow path from the heating element to the walls of the cavity. The amount of heat provided to the steam generating cavity is a function of wattage output from the adjacent sections of the heating element, the cross-sectional area of the heat flow path, the surface area of the boiler and the coeicient of heat transfer of the material used. ln accordance with this invention, these factors are selected to limit heat transfer into the cavity to a rate not exceeding the heat required to convert liquid in the cavity to steam at .040 pound per minute at maximum iron heat settings. In'other words, the design of the boiler cavity with relation to the heating element is determined by the heat required to vaporize water at the maximum rate found usable in a domestic hand iron. With respect to the opening 23 through which liquid flows from the reservoir into the cavity, its minimum size is suHicient to permit flow of liquid into the cavity at a rate at least equal to the maximum vaporization rate. in a practical embodiment, there has been constructed an iron in accordance with this invention having a wattage of the entire heating element in the order of 1100 watts, a diameter for orifice 23 of .O55 inch, and a Vaporization rate from liquid in the cavity of .035 pound of water per minute at maximum iron temperature. Such an iron was remarkably free of dry iilm ditiiculties and from obstruction of the opening 23, from scale particles, and the like.

The molded steam control housing 2) is further provided with an upwardly extending portion, including a steam passage 26 having an aperture 27 near its upper end opening into the upper portion of the reservoir. The steam passage 26 serves to permit the steam formed within the boiler to pass upwardly from the boiler and further serves to guide the steam into the upper portion of the reservoir. Also, the steam passage 26 is a pressure balance tube which equalizes the pressure in the boiler and the reservoir to insure proper water ilow through opening 23 into the boiler. In order to obtain quick steaming operation when starting with a cold iron, it is desirable to restrict the circulation of steam within the reservoir. For this purpose, there is provided a baille 28 which extends upwardly from the bottom of the reservoir `to the top and includes a hori- Azontally extending portionV 29 which serves as a support member for valve stem 24, as will be later described. The baffle 28, which also acts as a support member for the reservoir 15, is suitably apertured to permit liquid flow within the reservoir.

To conduct the steam from the upper portion of the reservoir to the steam passage and subsequently steam ports 11, the upper portion of the molded steam control housing is uniquely provided with another passage or conduit having a high steam take-off opening 31. At the opening 31, the conduit is formed with two inwardly extending tips or nibs 32 which serve as a screen to prevent large akes of lime or other deposits from entering the discharge conduit. Since it is contemplated that the iron shown in the drawing may be operated as a spray iron as well as a steam iron, it is necessary that suliicient steam be available to power the spray mechanism. With one type of arrangement, a certain minimum pressure is maintained within the reservoir. Accordingly, the steam discharge conduit 3i) is provided with a pressure regulating valve which includes a valve member 33 which seats against annular shoulder 34 formed integral with the molded member 20. The valve member 33 is biased upwardly against its seat by a coil spring 35 abutting against the upper surface of soleplate 1. Thus, it will be apparent that when the steam pressure within the reservoir is Sullicient to overcome the resistance of spring 35, the valve will open, permitting steam to flow downwardly to steam passage 10 and out steam ports 11 onto the fabric being pressed. It should be noted that the spring 35 extends through an opening formed in cover liner 14 and that the liner further includes an upwardly extending annular shoulder 36 which guides and supports and seals against the housing 20 and its steam conduit 30.

Alternatively, a manually controlled steam valve may be employed to prevent the iiow of steam through the soleplate when a pressure build-up is desired to operate the spray mechanism.

Water may be added to or emptied from the reservoir 15 by means of a conventional opening defined in a funnel 4t) mounted on the front portion of the iron handle. The opening in funnel 40 communicates with an aperture 41 formed in the upper wall of a riser 42, which is, in turn, secured to the upper portion of reservoir 15. A water-tight seal between funnel 4i) and riser 42 is provided by gasket 43. The aperture 41 is controlled by a disk valve 44 supported by a washer 45 which is secured to valve stem 24. The valve disk 44 is biased upwardly by spring 45a surrounding valve stem 24 and resting on support portion 29. The Valve stem 24 is shown in its lower position, wherein valve 44 is spaced from opening 41 to permit liquid flow therethrough, and the lower end of valve stern V24 is blocking opening 23 leading to boiler 8. In this connection, it should be noted that the lower end of valve stem 24 is provided with a guiding pin 46 which insures that the valve stern is guided into opening 23 when control button 25 is depressed. The pin 46 further serves to dislodge any large lime particles or other deposits which might tend to clog the opening 23. With this construction, a single manually operated valve stem 24 controls both the reservoir water inlet as well as its outlet.

When adding water to the reservoir, the iron is, of course, placed upon its heel rest in a conventional manner. To facilitate the filling operation, it is desirable that provision be made for escape of the air in the reservoir being displaced by the water. For this purpose, steam discharge valve 33 has been provided with a centrally located internal passage 47 and a. ball check valve 48 whichprevents the passage of steam through the passage 47 during the ironing operation. However, when the iron is placed upon `its heel rest, the ball 48 moves by gravity away from its seat on valve 33, thus permitting air to escape from the reservoir during the filling operation. It should be noted that the tips or nibs 32 of conduit 30 retain the ball 48 within the conduit when the ball has fallen away from valve 33. Moreover, if the reservoir is to be emptied byA means of openings 40 and 4T., the ball 48 will again roll away from valve 33, thus permitting air to enter the reservoir as the water is rer moved.

As another aspect of the invention, it should be noted that the liquid supply opening 23 between the reservoir and the steam generating cavity is positioned adjacent the most rearward wall of boiler 8. It should also be noted that the boiler walls taper from a larger diameter at the upper surface of the soleplate to a smaller diameter at the bottom of the boiler. The purpose of this arrangement is to drain the liquid from the steam generating cavity when the iron is placed on its heel rest. With the opening situated as described, the water within the boiler Will flow back into the reservoir through opening 23, and thus generation of steam will cease while the iron remains in its rest position.

As previously mentioned, provision has been included for a spray operation, wherein a steam and liquid spray is directed to the fabric in front of the iron. For this purpose, a tube 50 secured to the upper surface of riser 42 ducts steam to a spray mechanism 51. Since the details of the spray mechanism do not form a part of the present invention, a description of such is not included. The spray mechanism may be operated by a manual pushbutton 52 in accordance with several known arrangements, a preferred construction being described in detail in Patent No. 3,041,757 issued to A. G. Swenson and H. S. Foster, and assigned lto General Electric Company, assignee of the present application.

In operation, water is added to the iron by placing the iron upon its heel rest and depressing control button 2.5 to open valve 44, so that the water may be poured through inlet funnel 40 and reservoir aperture 41. With the valve stem 24 remaining in this depressed position, water is not permitted to flow into steam generating chamber 8. Accordingly, the iron may be operated as a dryviron in this condition.

If steam is desired, either for discharge through the soleplate or for the spraying operation, valve stem 24 is allowed to move upwardly by releasing manual control button 25. Water immediately flows from the reservoir through opening 23 into the boiler 8 until the boiler is ilooded with water. Assuming that the iron is connected to a source of current and that the temperature control has been set to a temperature sufficiently high to raise the walls of the boiler to at least the boiling temperature of water, steam will be generated along the boiler walls. The steam will bubble upwardly through the liquid in the boiler cavity, then through passage 25 in the insulated steam control housing, through opening 27 into the upper portion of reservoir 15. In bubbling through the remaining boiler water, the steam remains at a relatively low temperature and thus provides wet or saturated steam. When the steam pressure within the reservoir has reached a level sucient to overcome the bias of spring 3S, the steam passes through opening 3l into conduit 30, and downwardly to steam passage l@ and out steam ports 11 to the fabric being pressed. Thus, the steam passages 26 and 30 separate the steam from the boiler water to prevent water from passing through the steam discharge ports. It has been found that with the llooded boiler arrangement shown, the steam emanating from the soleplate ports is approximately 150 F. cooler than the steam emanating from a similar iron utilizing a ilash steam generator at usual steaming temperatures. At the lower temperature, the steam is, of course, much more usable in that the steam quickly condenses onto the fabric being ironed,

It will be appreciated that with the arrangement shown the steam generation rate is determined by the rate that heat is transferred to the boiler. It has been found that for typical household operation it is desirable to have steam generated at a rate certainly no greater than .O40 pound per minute. It is, of course,` essential to obtain such control of the heat transfer rate while keeping the remainder of the soleplate ysurface at its desired temperature level. The heat transfer rate may be controlled by properly spacing the boiler cavity from the heating 6 element and by proper selection of the area of the cavity forming the boiler.

The fact that the steam rate varies directly with the impressed heat reaching the boiler water provides advantageous ironing operation in that the materials requiring a high temperature ironing surface generally require large quantities of steam for good ironing results. Conversely, materials needing lower temperature need less steam.

If it is desired to utilize the spray mechanism 5l to fur-ther dampen the fabric, it is only necessary to depress manual control button 52.

Since the boiler is designed to remain flooded whenever the iron is in the ironing position, the iron would continue to provide steam for a short period of time when placed on its heel rest if the water were not drained from the boiler; that is, the water in the boiler would be converted to steam. To prevent the waste of this water and to eliminate undesired steam generation when the iron is at rest, the boiler 8 and opening 23 have been uniquely arranged so that the water will drain from the boiler back into the reservoir when the iron is placed on its heel rest.

While the present invention has been described by reference to a particular embodiment, it is to be understood that numerous modifications may be made by those skilled in the art without actually departing from the invention. Accordingly, it is to be understood that the following claims are intended to define the invention and all modifications thereof which come within the true spirit and scope thereof.

What I claim is:

l. In a atiron having a soleplate, a liquid boiler for generating steam, means for heating said soleplate and boiler, and a water reservoir overlying said boiler, a liquid passage from said reservoir to said boiler maintaining the boiler in a ooded condition, a steam conduit of insulating material extending upwardly from said boiler into said water reservoir for permitting the steam formed in said boiler to separate from the water in the boiler and pass upwardly into the Water reservoir and thus equalize pressure between the boiler and the reservoir, baffle means surrounding said conduit for limiting the circulation of steam within said reservoir, and means for conducting the separated steam to the fabric being ironed,

`2. In a pressing iron having a soleplate, a steam generating chamber, heating means for said soleplate and chamber, and a water reservoir overlying said chamber, a molded steam control housing of heat insulating material separating the boiler cavity from the reservoir, said housing having an opening for permitting a limited iloW of water into said boiler cavity suicient to maintain said cavity in a flooded condition, said molded member including a portion extending upwardly into said water reservoir and having an opening in its upper end for permitting steam formed in said boiler cavity and water carried up by steam to enter the upper portion of said Water reservoir land thus separate, said molded member further including a conduit for conducting steam from said reservoir to the fabric being ironed.

3. A pressing iron comprising a soleplate, a heel rest, a boiler for generating steam, a heating element for heating said soleplate and said boiler, a Water reservoir, a passage for permitting limited water ow between said reservoir and said boiler, said passage being suiciently large to maintain said boiler in Hooded condition while the iron is in operating position, means to separate water from steam generated in said boiler and to balance pressure between said reservoir and Vsaid boiler, means to conduct said separated steam to the fabric being ironed, and wall means forming part of said boiler for draining water from said boiler to said reservoir to terminate steam generation when the ironis placed on said heel rest. I

4. In a tlatiron having a soleplate, a steam generating chamber having at least one wall positioned in heat transferning relation with respect to said soleplate, means for heating said soleplate, a housing made of heat insulating material forming a wall of said steam generating chamber other than said one wall, a water reservoir insulated from said chamber by said housing, a water passage connecting said reservoir to said steam generating chamber for permitting Water flow into the chamber at a rate greater than the rate at which steam is formed within the chamber thereby maintaining the chamber in a ooded condition, said housing including means formed of heat insulating material and opening into said water reservoir -at a point above the reservoir normal maximum water level to thereby balance the pressure between said chamber and said reservoir and to permit steam to separate from the water in the chamber and tlow freely into the upper portion of said reservoir, said housing having a conduit formed of heat insulating material for conducting steam from said reservoir to the fabric being pressed.

5. In a pressing iron having a soleplate, a steam generating chamber, heating means for said soleplate and chamber, a water reservoir overlying said chamber, a molded steam control housing of heat insulating material separating said steam generating chamber from said reservoir, said housing having an opening to discharge liquid from said reservoir into said chamber at a rate suicient to maintain said cavity in a Hooded condition while in normal ironing position, said molded member including a portion extending upwardly into said reservoir and above the maximum liquid level therein with an opening above the liquid level for supplying steam from said chamber into the upper portion of said reservoir, said molded housing further including a steam discharge conduit for conducting steam from the upper portion of said reservoir to the fabric being ironed, a valve seat in said discharge conduit, and a spring biased valve cooperable with said valve seat to maintain operating pressure within said reservoir above atmospheric pressure.

6. In a pressing iron having a normal ironing position and anupended heel rest position, a soleplate, a steam generating chamber, heating means for said soleplate and chamber, a water reservoir overlying said chamber in normal ironing position, a molded steam control housing of heat insulating material separating said steam generating chamber from said reservoir, said housing having an opening to discharge liquid from said reservoir into said chamber at a rate sufficient to maintain said cavity in a ooded condition while in normal ironing position and to discharge liquid from said chamber back into said reservoir when in said upended rest position, said molded member including a portion extending upwardly into said reservoir and above the maximum liquid level therein with an opening above the liquid level for supplying steam from said chamber into the upper portion of said reservoir, said molded housing further including a steam discharge conduit for conducting steam from the upper portion of said reservoir to the fabric being ironed, a vaive seat .in said discharge conduit, and a spring biased valve coopera'nle with said valve seat to maintain an operating pressure within said reservoir above atmospheric pressure.

References Cited in the tile of this patent UNITED STATES PATENTS 2,483,580 Green et al Oct. 4, 1949 2,833,061 Franklin et al May 6, 1958 2,837,847 Franklin et al lune 10, 1958 2,878,600 Burmeister et al Mar. 24, 1959 2,878,601 Burmeister et al Mar. 24, 1959 FOREIGN PATENTS 809,402 Great Britain Feb. 25, 1959 

1. IN A FLATIRON HAVING A SOLEPLATE, A LIQUID BOILER FOR GENERATING STEAM, MEANS FOR HEATING SAID SOLEPLATE AND BOILER, AND A WATER RESERVOIR OVERLYING SAID BOILER, A LIQUID PASSAGE FROM SAID RESERVOIR TO SAID BOILER MAINTAINING THE BOILER IN A FLOODED CONDITION, A STEAM CONDUIT OF INSULATING MATERIAL EXTENDING UPWARDLY FROM SAID BOILER INTO SAID WATER RESERVOIR FOR PERMITTING THE STEAM FORMED IN SAID BOILER TO SEPARATE FROM THE WATER IN THE BOILER AND PASS UPWARDLY INTO THE WATER RESERVOIR AND THUS EQUALIZE PRESSURE BETWEEN THE BOILER AND THE RESERVOIR, BAFFLE MEANS SURROUNDING SAID CONDUIT FOR LIMITING THE CIRCULATION OF 